The invention relates to a laser knife, and more particularly to a laser knife of the type which is used to cauterize the tissues of an affected part located within the coeloma with laser radiation for purpose of excision or coagulation.
The conventional practice in the incision or excision of an affected part such as a polyp located within the coeloma has been by the use of excision or incision knife which is inserted into the forceps channel formed by a flexible tube of an endoscope and which is moved into or out of the distal end of the tube. However, the use of such excision or incision means requires a high level of skill and is also time consuming. In addition, treatments such as stanching or sterilization must be performed, resulting in a tremendous operation. An attempt has been made to avoid such disadvantages by using laser radiation which is directed toward an affected part to irradiate and cauterize it for purpose of excision or incision. While such a technique is advantageous in that the necessity of stanching or sterilization is avoided, the very high intensity of laser radiation employed involves the risk that unintended parts of the physical body may be irradiated after the radiation has been effectively utilized to cauterize the intended part, thus causing undesirable cautery or piercing of normal tissues. Nevertheless, it is appreciated that the surgical operation such as excision or incision could be simply completed within a very reduced length of time if provision is made to avoid an unintended irradiation with laser radiation.